I am the version of Ubuntu18. The process of installing php7.1,
through source code is as follows:
1. Extract the installation package php-7.1.18.tar.gz
2. Configure installation variables (to be simpler, mainly "/ usr/local/php" is the installation path)

./configure --prefix=/usr/local/php --with-curl --with-freetype-dir 

3. Then make and make install
4. Configure PHP

cp /usr/local/php-7.1.18/php.ini-development /usr/local/php/php.ini

Nginx is configured. Print phpinfo () results as follows

found that the location of php.ini is / usr/local/php/lib should not be under / usr/local/php/? And there is no php.ini in the / usr/local/php/lib directory
how do you understand this phenomenon? My PHP project can run without affecting